Walker Riserless Core - 3rd year review of a Rocket Mass Heater 

I am grateful for the fact my parents used English like a secret language. It made me motivated to learn when I was really young. I read Lord of the Rings when I was 14 or so 🤣

Thank you so much. We miss it when we are away ^_^

Cheers, that's exactly why I made this video. I also like to have a nice video to refer people to when explaining this kind of heater. Because it can be hard to relay how they work if you're not standing next to it.

55m2, which translates to about 600ft2.

@@futurecaredesign Thanks! That gives me a lot of comfort since those are about my exact measurements.

@@quest_onchannel54 Sweet! Keep in mind that our house was insulated from the outside with about 2 inches of styrofoam insulation. The rest of the building on the inside therefore acts like a thermal battery as well. That really improves our comfort levels. If you place a RMH in a log cabin it will behave different from a framed building and different again from a mortar and brick building. I hope I am making sense here but I am sure you will have gotten quite a bit of experience by now. What model did you build?

@@futurecaredesign The tiny cook stove. Its pretty neat! But I'm still not getting serious oven or bench temps. But I built a huge bench too. I'll post a video on mine after this winter to explain my process of building and experience. Our house is a framed building. Pretty warm so far but hardly any serious cold yet!

In one sentence? Central heating heats your skin, but not your core. RMHs heat your core, but not your skin. I must admit that I don't know how much we would normally use because we have only lived here with this heater. However I can tell you that the 'heat yourself on one tenth of the wood' meme comes from the following: It is much MUCH more efficient to heat people, than air. You could sit outside on a RMH bench on cold winter's day, and you would not feel cold. Because your butt is in contact with a warm surface. That heat conducts through the bench into your body and you just FEEL SO WARM. But that doesn't mean that if your put this heater in your house, your whole house will be warm. If you have a 150m2 house, only the heater and maybe the room it is in will be warm. What we are doing here is replicating what people have always done: Heat one room really well and kinda withstand the cold everywhere else in the house. Luckily our house is small and insulated, so we get more value out of our wood. But when you are busy in the kitchen around 4 or 5 in the afternoon you will feel quite cold. A thick sweater and warm slippers are required. And this is Greece, I imagine it gets more cold where you live. If I had to estimate it, I would say we use about 2/3rds of what we would burn if this was a regular fireplace/stove. But the value in heat we get OUT of that same wood, is much higher. Edit: I got the plans from Matt Walker, his website is the second link in the description. Or rather, I copied them from videos and pictures that he shared. And through discussion with him through forums. All of the plans for this stove are in the description too, just in Sketchup (3D model) format.

The 10% figure Is NOT from Walker Stoves. I would like to know whether the wood needs to be extra small and whether the box stove is more convenient to operate.

@@futurecaredesign What length and thickness of wood pieces do you use? It is hard to judge based on the photo. In America we use hefty 16 inchers but over there you probably use shorter lighter pieces anyway. I am trying to find out what Walker Stoves require.

Cheers. I haven't measured the exit flue but I imagine it isn't too warm. The single walled flue hasn't started giving off those rainbow colors if you know what I mean. Generally when a flue heats up too much and glows for a while it can really impact the stainless steel pipes. But that hasn't happened. It seems like youtube cut off your comment though, I can't read everything you wrote.

When the bell is larger than recommended you risk reducing the draft too much. In that case the bypass needs to be opened. Matt has done a video on this but I don't recall the name.

This is called the 'Walker Riserless Core', its an early version of the tiny cook stove and uses insulated firebricks. You can find the plans here: walkerstoves.com/product/full-masonry-cook-stove-complete-plans/ And the original website for it here: web.archive.org/web/20200213075233/walkerstoves.com/walker-riser-less-combustion-core.html

I would say about 6 meters. Inside of the living-room it is thinwalled flue pipe and then above the roof it is double wall and insulated with about 5cm of rockwool. Both types of flue are stainless steel and capped with a cone-shaped hood. The burn is so clean that not even two minutes after lighting it the white smoke disappears and the chimney looks like its not in use.

Me and one worker did the base, the piping and the the core. Then we had a professional bricklayer come in to do a dressing of firebricks all around the insulated core. I could have done this last part by myself but to be very fair: I am not a very good bricklayer and it would not have turned out as nicely as it did. The original top and the door were made by a friend of ours. The door is still there and working, the cooktop was 8mm thick steel and it bent out of shape within the first ten minutes of firing it up. It still worked fine but looked very ugly. So during the next summer we worked with a local fireplace builder to replace it with this cast-iron top.

I assume you would describe what I built an L-shaped firebox? The big difference is that this firebox is not as high. Another way to say that is 'the whole stove is lower'. For me this is positive for two main reasons: - It's allowing me to raise it off the ground, enabling us to see the fire from our couch. - It enables us to cook on it comfortably (its the right height and it has different heat 'settings', dependent on where you place the pot)